Mechanisms of Mindfulness-based Interventions

fMRI BOLD response to emotional word stimuli baseline to 12 weeks (post-MBCT). BOLD signal change (pre- to post-MBCT) is estimated from the contrast of emotional word vs neutral words, and extracted from voxels within the fronto-parietal and default mode areas at baseline and 12-weeks. Significant Voxel-wise BOLD activity is reported using z-scores from peak voxels. A mean score was calculated based on z-score and SD of 2 in the context of reporting fMRI BOLD data here. Z-scores is a statistical measure that describes how many standard deviations a data point (e.g., a voxel's signal) is from the mean of the distribution of that signal. The higher the reported mean, the less likely the observed activation is due to chance, thus indicating more significant activity or activation in that particular brain region.

Time frame: Baseline to 12 weeks

Population: Only 16 participants in Mild to moderate depression and/or anxiety participated in fMRI data collection. Participants in the High Stress Arm/Group were not assessed using fMRI and the subgroup was smaller given financial constraints.

P1 Evoked event-related electrical potentials (ERP) amplitudes elicited from specific emotional threat vs. neutral stimuli were primary outcome. An 80-150 ms search window at EEG electrode P8 was used to identify the P1 peak, & mean value around peaks (50 ms) was exported for analysis. Mean P1-Cue amplitudes were analyzed pre- to post-MBCT to determine the effects of time (pre to post-MBCT), emotion (angry vs. happy), and congruency (congruent vs. incongruent). Mean P1-Cue amplitudes in microvolts and SD for each condition are summarized below.

Time frame: Baseline to 12 weeks (pre- to post-MBCT)

Population: only depression/anxiety cohorts participated in ERP analyses. High stress group was not analyzed using ERP analyses

Effects of time (pre-MBCT versus post-MBCT), emotion (angry versus happy), and congruency (congruent probes versus incongruent probes) on reaction time (RT) was measured in mild to moderate depression/anxiety group.

Time frame: Baseline to ~12 weeks

Population: Only Mild to moderate depression and/or anxiety cohort who completed MBCT was analyzed for the dot-probe task. Data for this assessment was not collected from participants in the High Stress Arm

The Depression & Anxiety Stress Scale (DASS-Anxiety) (Lovibond and Lovibond, 1995) is a 7-item measure designed to assess symptoms of fear and autonomic arousal. Items are rated on a 4-point scale, ranging from 0 (did not apply to me at all) to 3 (applied to me very much or most of the time), and summed to compute the total scale (range 0-21). Higher scores are indicative of greater symptom severity, with scores greater than 10 typically considered of clinical significance. The DASS-Depression is a 7-item measure designed to assess dysphoric mood. Items are rated on a 4-point Likert scale, ranging from 0 (did not apply to me at all) to 3 (applied to me very much or most of the time), and summed to compute the total scale (range 0-21). Higher scores are indicative of greater symptom severity, with scores greater than 10 typically considered of clinical significance.

Time frame: Baseline to ~12 weeks pre- to post-MBCT (depression/anxiety cohort)

Population: Only 50 of the Depression and anxiety cohort who completed MBCT were tested on DASS-Anxiety and DASS-Depression pre/post MBCT; High Stress cohort was tested using the Perceived Stress Scale and reported in other outcomes

The Perceived Stress Scale (PSS-14) is a 14-item scale, with a total range from 0 (no symptoms) to 56 (highest severity) Higher scores are indicative of greater symptom severity, with scores greater than 10 typically considered of clinical significance.

Time frame: Baseline to ~12 weeks pre- to post-MBSR (high stress cohort)

Population: Only the High Stress cohort was tested using the Perceived Stress Scale (PSS-14); Depression and anxiety cohort was tested on DASS-Anxiety and DASS-Depression and reported in other outcomes